Escalator handrails used for escalators comprise composite materials each including a metallic steel wire, a thermoplastic resin, a canvas, etc., and are profile shape products each comprising the composite material in which the metallic steel wire is placed in the thermoplastic resin. In Patent Document 1, there is described a manufacturing method of a tire which comprises a resin-metal composite material comprising a resin material and a metallic steel wire. According to the resin-metal composite material in Patent Document 1, the adhesive strength therein has been enhanced using a treatment liquid (special treatment liquid) that contains a silane coupling agent and has a contact angle of 80° or less. The manufacturing method of the resin-metal composite material in Patent Document 1 comprises: applying a solution of the si lane coupling agent, that has been prepared by diluting it with water including an alcohol or a surfactant, onto the metallic steel wire followed by sintering at 110° C.; and then subjecting the wire to integral molding by incorporating it into the resin; so that a pull-out strength of the metallic steel wire relative to the resin is intended to be enhanced.
Further, the tire in Patent Document 1 is described: to use a cord of metallic steel wire formed of a mono-filament (single wire) of a metal fiber or a multi-filament (strand wire) provided by twisting such metal fibers; and to be provided as a superior one in adhesion property between the resin material and the metallic steel wire, because of the use of the special treatment liquid, even when the multi-filament is applied as the metallic steel wire.